docs: def DateTimeField(formatter=types.DEFAULT_DATETIME_FORMAT, default=NOTHING,
                    required=True, repr=True, cmp=True, key=None):
      """
      Create new datetime field on a model.
  
      :param formatter: datetime formatter string (default: "ISO_FORMAT")
      :param default: any datetime or string that can be converted to a datetime
      :param bool required: whether or not the object is invalid if not provided.
      :param bool repr: include this field should appear in object's repr.
      :param bool cmp: include this field in generated comparison.
      :param string key: override name of the value when converted to dict.
      """
      default = _init_fields.init_default(required, default, None)
      validator = _init_fields.init_validator(required, datetime)
      converter = converters.to_datetime_field(formatter)
      return attrib(default=default, converter=converter, validator=validator,
                    repr=repr, cmp=cmp,
                    metadata=dict(formatter=formatter, key=key))